strace gives lot of output. Work backwards and find the failure. Look for the error message in the strace output. Find the cause by reading the strace output. Find the offender and write down your hypothesis. Prove your hypothesis. Find the offender. Fix the bug.

0. Forget everything you think you know.
1. Get a third party opinion.
2. Refer the 'Linux Performance Tools' diagram for a list of third-party tools.

0. Forget everything you think you know.
1. Get a third party opinion.
2. Locate the correct source code.
3. Identify a hard-coded string to grep for.
4. Stare at the code until it makes sense.
5. Fix whatever is broken.